Istio Wasm Plugin Not Loaded

You encounter a istio configuration issue that prevents your workflow from completing. This guide walks through the fix step by step.

Wrong ❌

apiVersion: extensions.istio.io/v1alpha1
kind: WasmPlugin
metadata: { name: my-wasm }
spec:
  selector: { matchLabels: { app: my-service } }
  url: oci://registry.example.com/my-wasm:latest
  # Missing pluginConfig and phase

Wrong Output

WasmPlugin deployed but not loaded. No Wasm filter in Envoy config.

Right ✅

apiVersion: extensions.istio.io/v1alpha1
kind: WasmPlugin
metadata: { name: my-wasm }
spec:
  selector: { matchLabels: { app: my-service } }
  url: oci://registry.example.com/my-wasm:v1.0.0
  phase: AUTHN
  pluginConfig: { key: value }
  imagePullPolicy: Always
  imagePullSecret: regcred

Right Output

Wasm plugin loaded. Envoy config shows the Wasm filter. Traffic processed.

Prevention

• Use OCI-based Wasm images for versioned deploys.
• Specify phase for correct filter placement.
• Set imagePullPolicy and imagePullSecret for private registries.
• Verify with istioctl proxy-config cluster.
• Monitor Wasm log output from istio-proxy.

DodaTech applies similar defensive patterns across Doda Browser, DodaZIP, and Durga Antivirus Pro infrastructure for production reliability.

Common Mistakes with wasm plugin

1. Forgetting deriving (Show, Eq) on custom data types needed for debugging
2. Placing the wildcard pattern first in case expressions, making all subsequent patterns unreachable
3. Using head and tail instead of pattern matching, causing runtime errors on empty lists

These mistakes appear frequently in real-world ISTIO code. DodaTech's contributors have identified these patterns through analysis of open-source projects and production systems.

Practice Exercise

Write a pure function that safely divides two integers using Maybe, then test it with edge cases like division by zero and negative numbers.

This exercise reinforces the concepts covered in this guide. Try implementing it before checking online solutions.

FAQ

This quick fix is part of the DodaTech infrastructure engineering series. Learn more at DodaTech tutorials.